This invention is in the field of lasers having selectable wavelengths.
A normal laser, because of its construction, is capable of having an output of a number of wavelengths about some nominal wavelength. Various techniques have been proposed for selecting a particular output wavelength. U.S. Pat. Nos. 3,928,817, 4,425,648, and 4,575,243 are exemplary of such techniques. Also, on pages 588-590 of APPLIED PHYSICS LETTERS, Vol. 29, No. 9 of Nov. 1, 1976 and on pages 3986 and 3987 of APPLIED OPTICS, Vol. 21, No. 22 of Nov. 15, 1982 we see more techniques. This invention arose because of a need for a laser capable of rapidly providing a colinear sequence of different wavelengths. Although some of the references above can provide rapid wavelength changes, and some provide colinear beams, none of them can provide both, with low jitter. The instant invention does.